KR100227896B1 - Torque control method as power on to down-shift - Google Patents

Abstract

The present invention relates to a torque ratio control method for a power on down shift applied to an electronically controlled automatic transmission (A / T) of a vehicle. A first step of doing; A second step of determining whether an operating condition is satisfied using the throttle opening degree and its derivative value when the power-on shift mode is used in the first step; A third step of reading the torque ratio corresponding to the derivative value of the throttle opening degree and calculating the turbine speed of the torque converter when the operating condition is satisfied in the second step; A fourth step of allowing data relating to the turbine speed and torque ratio obtained in the third step to be transmitted from the shift control unit to the engine control unit; A fifth step of correcting the turbine speed and the torque ratio transmitted from the transmission control unit to the torque ratio of the current engine; A sixth step of calculating a target engine speed from the corrected torque ratio obtained in the fifth step and various sensor inputs; And a seventh step of performing fuel injection and ignition timing control of the engine as the target engine speed obtained in the sixth step, wherein the engine is controlled by the engine control unit according to the torque ratio determined by the shift control unit. It is possible to reflect the sudden acceleration will, and to improve the initial power generation acceleration performance, and by not using the damper clutch can prevent hunting of the damper clutch during uphill driving and improve the durability of the damper clutch.

Description

Torque Ratio Control Method of Power-On Downshift of Electronically Controlled Automatic Transmission

1 is a flowchart of an algorithm performed in a shift control unit in a torque ratio control method during power on down shift according to an embodiment of the present invention.

2 is a flowchart of an algorithm performed in an engine control unit of a torque ratio control method during power-on-down shift according to an embodiment of the present invention,

3 is a graph showing a mapping relationship of torque ratios according to derivatives in the flowchart of FIG. 1;

4 is a block diagram of an automatic transmission to which the torque ratio control method according to the embodiment of the present invention is applied;

5 (a) and 5 (b) are graphs comparing the graphs of the rotational speed (engine and turbine) and the vehicle speed with respect to time according to the present invention and the prior art.

* Explanation of symbols for main parts of the drawings

1: shifting valve 11: shifting lever

2: shift control unit 3: engine control unit

4: automatic transmission 5: torque converter

6: engine 7: accelerator pedal

8: Throttle Valve 9: Throttle Position Sensor

The present invention relates to a torque ratio control method for a power on down shift applied to an electronic control automatic transmission (A / T) of a vehicle, and more specifically, power on down. It relates to a torque ratio control method that allows the torque ratio to be determined according to the driver's sudden acceleration intention and road conditions at the time of shift, and to maintain the desired torque ratio by allowing the engine to be controlled by this torque ratio.

Most electronically controlled automatic transmissions are equipped with a damper clutch in the torque converter for direct connection between the engine and the input shaft of the transmission to improve fuel efficiency.

The control to turn on / off the damper clutch is performed by determination and execution of a transmission control unit (TCU), which is an electronic control device.

The shift control unit determines the on / off operating conditions of the damper clutch by searching mapping data related to the damper clutch on / off previously stored in a predetermined memory device.

The system of the automatic transmission operating as described above does not correspond to the driver's willing acceleration, there is a disadvantage that can not prevent the change of road conditions, for example, the hunting (hunting) of the damper clutch according to the uphill, the slope.

An object of the present invention is to solve the above-mentioned disadvantages, by using the torque multiplication effect of the torque converter satisfies the driver's acceleration will, and measures to increase the running resistance according to the road conditions, such as uphill It is to prepare.

In the torque ratio control method according to the present invention, an appropriate torque ratio is determined in the shift control unit based on the determination of the driver's sudden acceleration and road conditions, and the determined torque ratio is transmitted to the engine control unit to control the engine as the desired torque ratio. It has its characteristics.

As a means for achieving the above object, the configuration of the torque ratio control method for the power-on downshift of the electronically controlled automatic transmission according to the present invention comprises: a first step of determining whether the power-on shift mode; A second step of determining whether the damper clutch operating condition is satisfied using the derivative value when the power-on shift mode is used in the first step; A third step of reading the torque ratio corresponding to the derivative value of the throttle opening degree and calculating the turbine rotation speed of the torque converter when the damper clutch operating condition is satisfied in the second step; A fourth step of causing data relating to the turbine speed and torque ratio obtained in the third step to be transmitted from the shift control unit to the engine control unit; A fifth step of correcting the turbine speed and the torque ratio transmitted to the transmission control unit to the torque ratio of the current engine; A sixth step of calculating a target engine speed from the corrected torque ratio obtained in the fifth step and various sensor inputs; And a seventh step of performing fuel injection and ignition timing control of the engine as the target engine speed obtained in the sixth step.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

1 is a flowchart of an algorithm performed in a shift control unit of a torque ratio control method during power on down shift according to an embodiment of the present invention, and FIG. 2 is a torque ratio control method during power on down shift according to an embodiment of the present invention. 3 is a graph showing a mapping relationship of torque ratios according to derivatives in the flowchart of FIG. 1, and FIG. 4 is a torque ratio control method according to an embodiment of the present invention. Fig. 5 (a) and Fig. 5 (b) are diagrams showing a comparison of a graph of a vehicle speed and a rotational speed (engine and turbine) versus a vehicle speed according to the present invention and the prior art according to the present invention. One graph.

First, referring to FIG. 4, a configuration of an automatic transmission to which a torque ratio control method is applied during power on and down shift of an electronically controlled automatic transmission according to an embodiment of the present invention will be described.

Referring to FIG. 4, the engine 6 is equipped with a throttle valve 8 that determines the amount of intake air that enters the intake manifold in conjunction with the accelerator pedal 7, and a throttle position sensor 9 that detects the opening degree. It is.

The crankshaft of the engine 6 is provided with a torque converter 5 composed of a pump and a turbine and transmitting the output of the engine to the transmission. The turbine of the torque converter 5 has a planetary gear. automatic transmission 4 including a gear.

A shift control unit 2 is connected to the automatic transmission 4, and the shift control unit 2 is connected to the engine control unit 3 so as to communicate with each other by a transmission channel. Various sensor signals are input to the shift control unit 2 to output the shift control signal and the damper clutch control signal to the automatic transmission 4, and the various sensor signals are input to the engine control unit 3 to ignition signals and fuel injection. The signal is output.

On the other hand, the automatic transmission 4 is connected to the shift valve 1 having the shift lever 11 operated by the driver.

In FIG. 4, Ne is the engine speed, Nt is the turbine speed of the torque converter 5, and No is the speed of the drive axle.

Next, a torque ratio control method during power-on-down shift of the electronically controlled automatic transmission according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3 based on the automatic transmission structure of FIG.

Before explaining the operation, it is assumed that various sensor signals necessary for control are input to the shift control unit 2, and the derivative value of the throttle opening degree input from the throttle position sensor is calculated in advance in predetermined cycle units.

When the vehicle starts to drive (S1), it is determined whether a shift has occurred (S21), and if a shift has occurred, the process proceeds to the next step. The shift is generated, and it is determined whether the shift-on mode is a power-on-down shift (S22). In step S22, only the power-on-down shift is carried out to the next step, which is only a power-on-down shift in the control method of the present invention. This is because the target torque ratio is controlled.

Next, in steps S31 and S32, it is determined whether the throttle opening degree is between the minimum value THMIN and the maximum value THMAX of the throttle opening degree for determining the start of operation of the present invention. Goes. The minimum value and the maximum value are reference values for determining the driver's willingness to accelerate, and must be matched in advance by a test. If the current throttle opening degree is not a value between the minimum value and the maximum value, the control to which the present invention is applied becomes meaningless, and it is not necessary to keep the input target torque ratio at a specific value.

Next, it is determined whether the derivative value dTH / dT of the throttle opening degree is larger than the predetermined reference value DTHDMIN (S33), and the process proceeds to the next step only when this is satisfied.

The derivative value of the throttle opening degree is a pre-calculated value. If the derivative value of the throttle opening degree is large, the driver kicks down quickly, and the driver has a willingness to accelerate.

3 shows the relationship of the input target torque ratio to the derivative value of the throttle opening degree, and the data relating to the input target torque ratio is previously stored in a predetermined memory device.

If the instantaneous throttle opening degree operation condition of step S33 is satisfied, an input target torque ratio corresponding to the derivative value of the throttle opening degree is fetched from the memory device (S4). Further, the turbine torque of the torque converter 5 at the time when the transfer time, preferably 0.3 seconds has elapsed after the power-on down shift is completed (S5). In order to calculate the turbine torque of the torque converter 5, the turbine rotational speed is required, and a factor according to the conditions of the road conditions is fed back to the turbine torque. After the step S5 is performed, damper clutch control is disabled (S6).

Next, the torque ratio for transmission to the engine control unit 3 is calculated from the fetched torque ratio and the calculated turbine torque, and this calculation formula is as follows.

TRECU = DTHD TNT

In the above formula, TRECU is the torque ratio transmitted to the engine control unit 3, DTHD is the torque ratio corresponding to the derivative of the throttle opening degree fetched from the mapping data, and TNT is the turbine torque after 0.3 seconds after the completion of the downshift.

The calculated torque ratio TRECU and the turbine speed are transmitted through the transmission channel between the shift control unit 2 and the engine control unit 3 (S7), and when the transmission is completed, control of the algorithm is returned (S8). ).

When data transmission to the engine control unit 3 is started, the operation in the engine control unit 3 starts (S91). When the operation is started, the engine control unit 3 receives the turbine speed and torque ratio from the transmission channel (S92).

When the data reception is completed, the received data is fetched, the throttle opening degree and the engine speed detected by the sensor are input (S93).

In addition, the throttle opening signal is filtered (S94), and the torque ratio to be controlled by the engine control unit 3 is calculated in consideration of the fetched torque ratio and turbine rotation speed and the filtered throttle opening degree (S95). That is, the torque ratio of the engine control unit 3 is corrected by the torque ratio transmitted from the shift control unit 2.

An example of the calculation formula of the torque ratio that the engine control unit 3 should control is as follows.

ATRECU-TRECU TPS 0.2

Here, ATRECU is the target torque ratio to be controlled, TPS is the throttle opening degree input to the engine control unit 3, and TRECU 0.2 is a calculation for correcting the degree of stepping on the throttle valve of the driver.

When the above torque ratio ATRECU is obtained, the target engine speed is calculated by multiplying the current engine speed by the torque ratio ATRECU (S96). When the target engine speed is obtained, the engine is controlled as the target engine speed (S97), and the electronic control unit 3 generates a predetermined fuel injection signal and an ignition signal.

When the engine control is completed through the generation of the fuel injection signal and the ignition signal, control of this algorithm is returned (S98).

On the other hand, although not shown in the flowchart of the method according to the present invention, other types of shifts (eg, power on up shift, power off up / down shift) occur after the power on down shift in the main routine of the shift control unit. If so, it immediately stops the control according to the method of the present invention and transmits a stop signal to the engine control unit 3 so that the engine control unit immediately returns to normal control.

Next, with reference to FIG. 5 (a) and FIG. 5 (b), the performance when applying the control method of this invention and the conventional technique is compared.

Referring to FIG. 5 (a), the dashed-dotted line is the engine speed according to the existing method, the solid line is the speed according to the existing method, and the thin dotted line is the engine speed according to the method of the present invention, and the thick dotted line Is the turbine speed according to the method of the invention.

As shown in FIG. 5 (a), when the control method according to the present invention is applied, it can be seen that the torque ratio is kept constant by increasing the engine speed and the turbine speed at a constant ratio.

Referring to FIG. 5 (b), the solid line is the vehicle speed according to the conventional method, and the dotted line is the vehicle speed according to the present invention.

As shown in FIG. 5 (b), it can be seen that the initial oscillation performance is improved when the present invention is applied.

As described above, according to the embodiment of the present invention, by controlling the engine in the engine control unit according to the torque ratio determined in the shift control unit, it is possible to reflect the driver's sudden acceleration will improve the initial start acceleration performance In addition, by not using the damper clutch, it is possible to prevent hunting of the damper clutch when driving uphill and to improve the durability of the damper clutch.

Claims (5)

Determining a power-on shift mode; A second step of determining whether the instantaneous throttle opening degree operation condition is satisfied using the throttle opening degree and its derivative value in the power on shift mode in the first step; A third step of reading the input target torque ratio corresponding to the derivative value of the throttle opening degree and calculating the turbine speed of the torque converter when the instantaneous throttle opening degree operation condition is satisfied in the second step; A fourth step of causing data relating to the turbine rotational speed and the input target torque ratio obtained in the third step to be transmitted from the shift control unit to the engine control unit; A fifth step of correcting the turbine speed and the target torque ratio transmitted from the transmission control unit to the torque ratio of the current engine; A sixth step of calculating a target engine speed from the corrected input target torque ratio and various sensor inputs obtained in the fifth step; And a seventh step of performing fuel injection and ignition timing control of the engine as the target engine speed obtained in the sixth step. The method of claim 1, further comprising disabling the control of the damper clutch between the third and fourth steps. The value corresponding to the current throttle opening degree derivative among the data of the torque ratio with respect to the derivative value of the throttle opening degree previously mapped to a predetermined memory device is fetched. And a torque ratio control method during power-on down shift of the electronically controlled automatic transmission. 2. The control operation according to claim 1, wherein the control operations of the first to third steps are performed by the shift control unit, the operations of the fifth to seventh steps are performed by the engine control unit, and the fourth step is shifted. A method of controlling torque ratio during power-on-down shift of an electronically controlled automatic transmission, characterized in that performed by communication via a transmission channel of a control unit and an engine control unit. The method of claim 1, further comprising, after the power on down shift, stops control immediately and transmits a stop signal to the engine control unit so that the engine control unit returns to normal control. Torque ratio control method for power-on downshift of the electronically controlled automatic transmission comprising a.